Date post: | 31-Mar-2015 |
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LabVIEWand “G” Graphical Programming Language
By: Ramtin Raji Kermani
What is LabVIEW?
LabVIEW (Laboratory of Virtual Instrument Engineering Workbench) is a development environment based on graphical programming.
What is LabVIEW?
LabVIEW relies on graphical symbols rather than textual language to describe programming actions
The principle of dataflow, in which functions execute only after receiving the necessary data, governs execution in a straightforward manner.
LabVIEW features
• Product of National Instruments (NI)
• Software for Virtual Instrumentation
• Data Acquisition (DAQ)
• Graphical Programming
• Data Storage and Analysis for wide Range of applications
LabVIEW features
LabVIEW programs are called:Virtual Instruments (VIs) because their appearence and operation imitate actual instruments.
However, they are analogous to main programs, functions and subroutines from popular language like C, Fortran, Pascal, …
Virtual Instruments
1- The front panel:
an interactive user interface of a VI, so named because it can simulates the front panel of a physical instrument.
2- The block (or wiring) diagram:It is the VI’s source code, constructed in LabVIEW’s graphical programming language, G. It is the actualexecutable program.
Subroutine in the block diagram of VI.
3- Icon/connector
VIs
Front Panel User Interface (UI)
Controls = Inputs Indicators = Outputs
Block Diagram Graphical Code
Data travels on wires from
controls through functions to indicators Blocks execute by Dataflow
Front Panel
Front Panel
a
A combination of controls and indicators.
Controls = Inputs from the user = Source Terminals
Indicators = Outputs to the user = Destinations
Block Diagram
Terminals
When you place a control
(or indicator) on the
FRONT PANEL
LabVIEW automatically creates a correspondingcontrol (or indicator) terminal on the BLOCKDIAGRAM
Control or Indicator Terminal?
Control terminals have
thick borders
Indicator terminals have
thin borders
Nodes
Node is just a fancy word for a program execution element –
Nodes are analogous to statements, operators, functions and
subroutines in standard programming language:
•The add and subtract functions represent one type of node.
•A structure is an other type of node. Structures can execute code repeatedly or conditionally, similar to loops and case statements in traditional programming languages.
•LabVIEW also has special nodes, called formula nodes, which are useful for evaluating mathematical formulas or expressions.
Control or Indicator Terminal?
Data Types
Each wire has different style or color, depending on the data
type that flows through the wire:
Scalar1D array2D arrayColor
Floating-point number
orange
Integer number
blue
Booleangreen
Stringpink
Type Checking
If you connect more than
one source or no source
at all to a wire,
LabVIEW DISAGREES with what you’re doing, and thewire will appear broken
ACTION !
Let get into Action…